slim-lint is a tool to help keep your Slim files clean and readable. In addition to style and lint checks, it integrates with RuboCop to bring its powerful static analysis tools to your Slim templates.

You can run slim-lint manually from the command line, or integrate it into your SCM hooks.

• Requirements
• Installation
• Usage
• Configuration
• Linters
• Editor Integration
• Git Integration
• GitHub Integration
• Rake Integration
• Contributing
• Changelog
• License

• Ruby 3.0+
• Slim 3.0+

gem install slim_lint

Run slim-lint from the command line by passing in a directory (or multiple directories) to recursively scan:

slim-lint app/views/

You can also specify a list of files explicitly:

slim-lint app/**/*.slim

slim-lint will output any problems with your Slim, including the offending filename and line number.

slim-lint will automatically recognize and load any file with the name .slim-lint.yml as a configuration file. It loads the configuration based on the directory slim-lint is being run from, ascending until a configuration file is found. Any configuration loaded is automatically merged with the default configuration (see config/default.yml).

Here's an example configuration file:

exclude:
  - 'exclude/files/in/this/directory/from/all/linters/**/*.slim'

linters:
  EmptyControlStatement:
    exclude:
      - 'app/views/directory_of_files_to_exclude/**/*.slim'
      - 'specific/file/to/exclude.slim'

  LineLength:
    include: 'specific/directory/to/include/**/*.slim'
    max: 100

  RedundantDiv:
    enabled: false

All linters have an enabled option which can be true or false, which controls whether the linter is run, along with linter-specific options. The defaults are defined in config/default.yml.

The exclude global configuration option allows you to specify a list of files or glob patterns to exclude from all linters. This is useful for ignoring third-party code that you don't maintain or care to lint. You can specify a single string or a list of strings for this option.

Some static blog generators such as Jekyll include leading frontmatter to the template for their own tracking purposes. slim-lint allows you to ignore these headers by specifying the skip_frontmatter option in your .slim-lint.yml configuration:

skip_frontmatter: true

To disable a slim-lint linter, you can use a slim comment:

/ slim-lint:disable TagCase
IMG src="images/cat.gif"
/ slim-lint:enable TagCase

To disable Rubocop cop, you can use a comment control statement:

- # rubocop:disable Rails/OutputSafety
p = raw(@blog.content)
- # rubocop:enable Rails/OutputSafety

You can find detailed documentation on all supported linters by following the link below:

Install the Sublime slim-lint plugin.

If you use Flycheck, support for slim-lint is included as of version 20160718.215 installed from MELPA.

Install the linter-slim-lint plugin by running apm install linter-slim-lint.

Install the VS Code slim-lint plugin.

If you'd like to integrate slim-lint into your Git workflow, check out overcommit, a powerful and flexible Git hook manager.

To run slim-lint in your GitHub Actions CI pipeline, use the github reporter, for example:

on:
  pull_request:
  push:
    branches: [ main ]

jobs:
  lint:
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Ruby
        uses: ruby/setup-ruby@v1
        with:
          ruby-version: .ruby-version
          bundler-cache: true

      - name: Lint Slim templates for consistent style
        run: bundle exec slim-lint -r github app/views

On lint failures, this setup will create annotations in your pull requests on GitHub.

To execute slim-lint via a Rake task, make sure you have rake included in your gem path (e.g. via Gemfile), and add the following to your Rakefile:

require 'slim_lint/rake_task'

SlimLint::RakeTask.new

By default, when you execute rake slim_lint, the above configuration is equivalent to running slim-lint ., which will lint all .slim files in the current directory and its descendants.

You can customize your task by writing:

require 'slim_lint/rake_task'

SlimLint::RakeTask.new do |t|
  t.config = 'custom/config.yml'
  t.files = ['app/views', 'custom/*.slim']
  t.quiet = true # Don't display output from slim-lint to STDOUT
end

You can also use this custom configuration with a set of files specified via the command line:

# Single quotes prevent shell glob expansion
rake 'slim_lint[app/views, custom/*.slim]'

Files specified in this manner take precedence over the task's files attribute.

We love getting feedback with or without pull requests. If you do add a new feature, please add tests so that we can avoid breaking it in the future.

Speaking of tests, we use rspec, which can be run by executing the following from the root directory of the repository:

bundle exec rspec

If you're interested in seeing the changes and bug fixes between each version of slim-lint, read the Slim-Lint Changelog.

This project is released under the MIT license.